Abstract
The postembryonic development of the olfactory organs was studied in developmental stages of the Nile cichild fish Sarotherodon galilaeus (= Tilapia galilaea) including 2 buccal stages (5 and 7 mm) and three postbuccal ones (9, 12 and 58 mm total length). In the buccal stages, the olfactory organ on each side is simple and represented by the olfactory epithelium and a narrow olfactory chamber opening externally through a single aperture on the dorsolateral surface of the snout. As development proceeds in the postbuccal stages, however, two accessory nasal sacs are developed: a dorsomedial sac and a ventrolateral sac, both are connected with the main olfactory chamber.